Polarization Masks: Monitors and High-Resolution Structures

Michael Lam1
(Professor Andrew R. Neureuther)

Rigorous electromagnetic simulations are used to test the lithographic printing of novel technologies such as polarization masks. Polarization masks use small bars inserted into features to polarize the incident radiation, allowing features to be printed with the chosen polarization. Proximity effects from electric field spillovers between adjacent features can be reduced by passing opposite polarizations, resulting in spatially orthogonal electric field vectors than give a reduction in intensity of _. Additionally, polarization bars can help mitigate the effects of large phase transitions on phase-shifting masks. Several special purpose monitors can be constructed with polarization bars to monitor polarization imbalances in the illumination, high numerical aperture effects on vector addition, as well as polarization dependent resist coupling effects. Small, dense contacts may also be produced by using a combination of polarization and phase shifting to generate four wave interference at the wafer. These polarization bars must have gap widths of about l/8 - l/3 with the bars themselves being about l/8.